Percutaneous coronary intervention (“PCI”), or “angioplasty”, is an invasive procedure that is used to open a blockage in a coronary artery, that is, an artery that provides blood to the heart. In a PCI procedure, a cardiologist inserts a catheter into an artery in the upper arm or thigh of a patient and guides the catheter through the arteries to the affected coronary artery. With the catheter in place, the doctor threads a guide wire across the blockage. After the wire is across the blockage and positioned distal to the blockage, the cardiologist then advances the catheter with a deflated balloon. The balloon is inflated to dilate the blockage to make enough room for the insertion of a second catheter with its own balloon and stent. After dilating the blockage, the balloon is deflated and the first catheter is removed proximally.
At this point in the procedure, complications can occur. For example, coronary dissections or ruptures in the wall of the artery can occur and shut down blood flow. If the guide wire, which is in position across the blockage, is lost or pulled back proximal of the blockage during the first catheter exchange, such an occurrence can result in a heart attack if rewiring the artery is not possible after breakage of the wall.
Assuming that such complications do not occur, the second catheter with another balloon and a stent or metal mesh surrounding the balloon is advanced distally along the guide wire to the area of the blockage. The second balloon is inflated, which expands the stent and completely opens the blockage. The second balloon is then deflated, leaving the stent in place, and the second catheter is then removed.
U.S. Pat. No. 5,226,889 to Sheiban (“Sheiban”) discloses a double balloon catheter for stent implantation. This catheter, however, has several drawbacks. Sheiban's proximal balloon and the distal balloon are only separated from each other by a small radiopaque marker. A drawback to this configuration is that visualization of the predilated angioplasty area is difficult to confirm. Further, the proximity of the distal balloon to the proximal balloon in Sheiban's catheter restricts the “pushability” of the catheter through narrow, tortuous, and sometimes occluded vessels. Without a significant separation between the two balloons, the interventionalist may have an extraordinarily difficult time advancing the catheter without causing trauma to the vessel walls.
An improved device for performing the above procedure without requiring the insertion and removal of two separate catheters is required.